Active Plasmonic Components and Metamaterials

Friday, February 20, 2009 - 3:00 p.m. to Saturday, February 21, 2009 - 3:55 p.m.
ChEMS Seminar

Featuring Dr. Harry A. Atwater

Thomas J. Watson Laboratories of Applied Physics
California Institute of Technology

Location: 1300 Donald Bren Hall

Abstract:
Dispersion control and active materials integration have yielded plasmonic components including i) three-dimensional single layer plasmonic metamaterials ii) all-optical, electro-optic and field effect modulation of plasmon propagation iii) plasmon-enhanced absorption in solar cells.  We expand upon recently reported work on direct observation of two-dimensional negative refraction in the visible frequency range to develop a general approach to realization of three-dimensional single-layer, all-angle, polarization-independent plasmonic metamaterials exhibiting negative refraction.  Full wave simulations and dispersion calculations are used to demonstrate that metal-dielectric-metal plasmonic structures are characterized by negative wave vectors and negative refractive indices.

Metal-dielectric plasmon waveguides can serve as active switching elements when the dielectric refractive index can be actively modulated.  We demonstrate electro-optic refractive index modulation in metal-dielectric-metal plasmon waveguides using low-voltage electro-optic modulation of both silicon and perovskites oxide dielectric layers.

The efficiency and cost effectiveness of photovoltaic cells can both be increased by reduction of the active semiconductor absorber layer thickness and ability to fabricate ultrathin absorber layers opens up new possibilities for solar cell device design.  The strong mode localization of surface plasmon polaritons at metal-dielectric interfaces leads to strong absorption in semiconductors thin films, enabling a dramatic (10-100X)  reduction in the semiconductor absorber physical thickness needed to achieve an optically thick film.  Modal analysis in full wave simulation allows us to determine the fraction of power absorbed by the solar cell to be determined for both dielectric and plasmonic modes.